Positive pressure resuscitator

ABSTRACT

Apparatus for the administration of gases such as oxygen, anaesthetic gases, and the like, incorporating a chamber adapted to communicate with a face mask, a gas delivery conduit for delivering gas into the chamber, a control valve manually operable to start and stop delivery of gas thereto, a vent opening for intermittently venting the chamber to atmosphere for exhalation, a valve stem and a valve operating button thereon, the valve stem extending through the vent opening to the exterior of the chamber, a vent closure comprising the inner surface of the valve button, closing the vent opening when the button is operated to start delivery of gas to the chamber, a pressure relief valve communicating with the chamber for discharging to atmosphere in the event of an overpressure occuring therein, while the vent closure is in position closing the vent opening; a gas bypass connection connecting with the gas delivery conduit for receiving gas independently of the control valve; a gas bypass flow valve manually operable between open and closed positions, and a gas bypass delivery conduit connecting with the chamber for delivery of gas directly thereto independently of the control valve.

This application is a Continuation-in-part of U.S. Pat. application Ser.No. 428,823, filed Dec. 27, 1973.

The present invention relates to apparatus for the administration ofgases such as oxygen, anaesthetic gases and the like and is particularlydesigned to provide a resuscitator appliance which may be used first asa resuscitator and subsequently as an inhalator.

BACKGROUND OF THE INVENTION

Respiration equipment may be divided into two main classes. The firstclass, namely resuscitators, are generally speaking designed forreviving a patient who has either ceased breathing, or who is breathlingonly with great difficulty. The other type of equipment, namelyinhalators, supply gases or gas mixtures such as anaesthetics, or oxygenenriched air for speeding up the revival of a person who either haspreviously been revived with a resuscitator, or who is experiencing somerespiration difficulty, and requires assistance.

In the great majority of cases, it is highly desirable to have the twofunctions namely the resuscitator function and the inhalator functionprovided by the same piece of respiration equipment, with complete andinstantaneous control over both functions without the need for leavingthe patient to attend to a complex system of valves and gauges. In thepast, dual-purpose apparatus of this kind has been available but hasbeen of such a complex and cumbersome nature that either the operatorwould have to turn away from the patient to attend to various dials andgauges, or he would require an assistant. The desired coordination ofthe assistant handling the controls, with the operator who is actuallyin charge of the patient was of course quite difficult to achieve inmany circumstances.

In addition, it is desirable to provide such a piece of equipment whichcan be operated in a simple foolproof manner by relatively unskilledpersonnel. It is of course be borne in mind that in many cases equipmentof this kind is used in an emergency by the first person who isavailable to assist a casualty. Such a person will only in very rarecases be a highly trained medical assistant. In the great majority ofcases such a person may be for example a lifeguard or swimming poolattendant, or a person on duty at an electrical generating station forexample, or may be a relatively untrained fireman. In addition, theenvironment where such treatment is given is rarely if ever conducive tothe careful and methodical application of professional medical skills.On the contrary, such an environment may be for example, several hundredfeet under ground in a mine shaft, or at a breakdown in a generating ortransformer station, or at the location of a fire. Such equipment musttherefore be adapted for use by such relatively untrained personnel, whomay in addition, be under considerable emotional or nervous strain dueto the circumstances and the surroundings.

A further factor which must be borne in mind is the fact that theatmosphere at the location may not be conducive to respiration at all.For example, at a fire, or in a mine shaft, the air will usually beheavily contaminated and scarcely fit to breath. It is therefore highlydesirable that such contamination shall be completely excluded from therespiration equipment.

As stated, equipment has been available in the past of a relativelycomplex nature which would provide the positive pressure resuscitationfunction, applying 100 per cent oxygen under positive pressure to thecasualty. However, it was difficult and cumbersome to convert suchequipment to the inhalation function to permit free breathing with airenriched with oxygen after resuscitation had been successfully carriedout. In addition, the control of such positive pressure apparatusrequired careful training and practice for satisfactory results whichwere not injurious to the casualty, for example, as a result of theapplication of an overpressure of oxygen to the lungs.

It is therefore desirable to provide a resuscitator apparatus which issimple to operate, and requires little or no training, and is designedto prevent accidental injury to the casualty, and which may readily beconverted to an inhalator function by the operator without distractinghis attention from the casualty.

BRIEF SUMMARY OF THE INVENTION

With these objectives in mind, the invention seeks to provide aresuscitator apparatus incorporating a passageway adapted to communicatewith a face mask, oxygen delivery means for delivering oxygen into saidpassageway, valve means for intermittently discontinuing delivery ofoxygen thereto, vent means for intermittently venting said passageway toatmosphere for exhalation, and, pressure relief valve meanscommunicating with said passageway for venting the same to atmosphere inthe event of an overpressure occurring therein.

More particularly, the invention seeks to provide a resuscitatorapparatus having the foregoing advantages in which the operation of thevent means is coupled to the operation of said oxygen valve means,whereby upon closure of said oxygen valve means said vent means issumultaneously opened, and whereby upon opening of said oxygen valvemeans or delivery of oxygen into said passageway, said vent means issimultaneously closed, thereby ensuring a positive pressure within saidpassageway for delivery of said oxygen to the casualty.

More particularly, it is an objective of the invention to provide adevice of the type described incorporating a pressure relief valve whichmay be preset accurately for preventing injury to the casualty due tomisuse of the equipment.

More particularly, it is an objective of the invention to provide adevice of the type described having the, foregoing advantagesincorporating a vent opening for exhalation by the casualty, whichopening is normally open to establish free air flow between the interiorand exterior of said passageway, and which is closed only by the actionof opening the oxygen valve to admit oxygen therein.

It is a further and related objective of the invention to provide adevice of the type described incorporating bypass conduit means forpermitting oxygen to flow directly into said passageway without passingthrough said oxygen valve, and valve means for controlling said oxygenbypass flow.

The foregoing and other advantages of the invention will become apparentfrom the following description of a preferred embodiment of theinvention which is given here by way of example only with reference tothe following drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sectional side elevational view of a resuscitator accordingto the invention.

DESCRIPTION OF A SPECIFIC EMBODIMENT

As shown in the illustration, the resuscitator apparatus according tothe invention will be seen to comprise a main body portion M and abypass control B.

Referring first of all to the main body portion M it will be seen tocomprise a tubular barrel 10 defining a hollow cylindrical chamber 12and having a lower tubular extension 14. The lower tubular extension 14will be of any suitable shape, and may have a slight exterior taper, ifdesired, so as to be fitted into one of a variety of different facemasks F. It will of course be appreciated that different types of facemasks may be used for different casualties, such face masks beingomitted from the drawing for the sake of clarity and being in any eventwell known in the art.

Within the chamber 12, an oxygen delivery pipe 16 is threadedly fastenedin the threaded opening 18. The oxygen delivery pipe 16 is provided withan outlet orifice 20 for discharging oxygen into the interior of thechamber 12. The pipe 16 extends outwardly from the main body 10, and isthreadedly connected to the bypass valve B described below.

Within pipe 16, there is a spring loaded valve unit 22 secured by sleeve23 and operated by means of a valve operating pin 24 extendingtherefrom. The valve 22 may be of any well known design such as is usedin automobile and truck tires, and is not illustrated for the sake ofclarity since the details are well known in the art. However, the valve22 would normally be closed, and would be opened upon pressure beingapplied to the operating pin 24, the valve unit 22 including a spring(not shown) urging the valve closed as soon as the pin 24 is released.

In order the apply axial pressure to the operating pin 24, a pressureshaft 26 is slidably mounted in the open end of the pipe 16, and extendsoutwardly therefrom beyond the exterior of the body 10. A button 28 isfastened to the free end of the shaft 26 whereby the same may bemanually pressed home to depress the operating pin 24 and open the valve22.

A retaining pin 27 engages a slot 29 in shaft 26 to retain the same inthe pipe 16.

In order to provide an exhalation port communicating between the chamber12 and the exterior of the body 10, a port or opening 30 is formed inthis body 10 co-axially with the oxygen pipe 16. The exhalation port 30is of a greater diameter than the pipe 16 whereby to define a free spacetherearound around which air may flow in or out sufficiently freely topermit respiration by a patient.

In order to close the exhalation port during positive pressureresuscitation, a closure seat 32 is formed around the port 30, and asealing surface 34 is formed on the underside of the button 28, which isdesigned to contact the seat 32 when the button 28 is depressed, andthereby close off and seal the exhalation port 30.

When button 28 is released it will be observed that it has sufficientclearance from the seat 32 to permit free flow of air into and out ofport 30 to permit respiration by a patient as described.

In order to provide a pressure relief valve, a valve chamber 36 isprovided at the top end of the body 10 formed essentially by an oversizecounterbore co-axial with the cylindrical chamber 12. Within the valvechamber 36 a disc-like valve plate 38 is provided, fitting snuglyagainst the valve seating surface 40. A supporting stem 42 extendsaxially upwardly from the center of the disc 38, and is supporting bythe adjustment screw 44, formed with a suitable cylindrical recess 46extending axially upwardly therein, and of a suitable size to permit thesupporting stem 42 of the valve disc 38 to slide inwardly and outwardly.

A spring 48 is fitted aroung the stem 42 and extends between the lowerend of the screw 44 and the upper surface of the disc 38, and normallyurges the disc 38 in to its closed or seated position.

A top closure plate 50 threadedly engages and closes the top of thevalve chamber 36, and is provided with a central threaded hole 52 forthreadedly receiving the screw 44. Thus by adjusting the screw 44inwardly or outwardly, the pressure exerted by the spring 48 on thevalve disc 38 can be precisely regulated. Preferably, such regulationwill be carried out in the factory, and the screw 44 will then be set sothat it cannot lose its adjusted position.

In order to provide a finish, and to prevent tampering with the screw 44any suitable cover means such as the adhesive metallic label 54 may beprovided extending over the central portion of the cover 50 andconcealing the screw 44. If desired, the cover 50 can be provided with athickened portion 56 to provide a somewhat greater length for thethreaded hole 52 thereby permitting a wider range of adjustment for thescrew 44.

In order to permit escape of oxygen, or exhaled oxygen and air, in somecases, from within the valve chamber 46, a number of radial ventdrillings 58 are formed at angularly spaced points around the main body10 communicating with the interior of valve chamber 36, and a pluralityof longitudinal vent drillings 60 are formed through the main body 10 atspaced points therearound, parallel with the central axis of the mainbody 10, and communicating with the annular recess 62. In this way, anoverpressure causing the valve disc 38 to lift, may be relieved eitherthrough the vent openings 58 or through the vent openings 60 and 62, thevent opening 60 communicating with the radial openings 58 so that in theevent for example all of the radial openings 58 are covered by the handsof the operator, the pressure can still nevertheless be vented throughthe drillings 60 and the annular opening 62.

The bypass control B will be seen to comprise a main body portion 70,formed with a transverse cylindrical chamber 72. The one end of thechamber 72 the main body 70 is threaded to receive the delivery pipe 16,and establishes communication between the chamber 72 and the interior ofthe pipe 16. At the other end of the chamber 72, pipe threads 74 areformed for communication with any suitable oxygen supply system,consisting of a cylinder, with or without reducing valves and pressuregauges, all of which are well known in the art. In the majority of casesa flexible pressure hose (not shown) will be connected to the pipethreads 74 thereby permitting freedom of movement of the entireresuscitator unit, such hose being omitted for the sake of clarity.

In order to provide a continuous regulated bypass flow of oxygen,bypassing the valve 22, the bypass conduit 76 is provided communicatingwith the interior of the chamber 72, and a right angle bypass pipe 78communicates between the lower end of the conduit 76, and enters thechamber 12 below the oxygen delivery pipe 16 as shown.

In order to regulate or entirely cut off flow of oxygen into the bypassconduit 76 and pipe 78, control is established by means of the taperedvalve member 80 mounted on the threaded valve screw 82, which isthreadedly received in a suitable threaded recess (not shown) formed inthe main body 70. A knurled knob 84 is fastened to the top end of thevalve screw 82 for rotating the same.

The tapered valve member 80 fits within a valve seat 86 fastened withinbypass conduit 76.

In operation, assuming the casualty requires positive resuscitation,oxygen will be supplied by any suitable source (as described above)directly into the chamber 72 of the bypass control B. At this point, thevalve 80 will be seated firmly in the valve seat 86 thereby shutting offthe bypass 76 and 80. Oxygen will thus be communicated directly to thevalve 22. It cannot pass the valve 22 at this point since it is closed.

The attendant will then place the face mask F over the nose and mouth ofthe casualty, or in the case of a child for example over its entireface, depending upon the type of mask in use. The attendant will thendepress the button 28 until the sealing face 34 contacts the seat 32. Atthis point, the valve pin 24 is fully depressed into the valve 22 andthe valve then passes oxygen through the interior of the pipe 16 and itcan then pass out of the pipe 16 in through the port 20. At the momentwhen the valve 22 is first opened gas flows rapidly through opening 20.Such gas flow will initially tend to evacuate that part of the chamber12 lying above the valve 22 and cause a slight momentary negativepressure. This will in turn draw the disc 38 more securely against theseat 40 thereby adding to the pressure of the spring 48. The flow of gasthen establishes a positive pressure oxygen within the chamber 12 whichis therefore communicated directly to the face mask F, and hence tocasualty's lungs. Oxygen cannot escape from the chamber 12 through theport 30 since this is sealed and closed by the sealing surface 34 of thebutton 28 as described above.

Assuming that the casualty has no obstruction in the windpipe, then theoxygen will dilate the lungs. As soon as the attendant sees the chest ofthe casualty rise he will then release the button 28 and apply a gentlepressure to the chest to force the casualty to exhale. The releasing ofthe button 28 shuts off the valve 22 so that there is no furtherpressure of oxygen within the chamber 12. At the same time, it opens theport 30 thereby establishing free flow of oxygen from the chamber 12 toatmosphere. The pressure on the chest of the casualty will thus causeany oxygen within the lungs to flow outwardly to atmosphere. Theattendant will then again press the button 28 and release the pressureon the casualty's chest, and continue until the casualty commencesnatural breathing.

Assuming that the attendant decides to continue supplying oxygen to thecasualty when he has started breathing, then all the attendant has to dois to simply turn the knob 84 so as to permit a metered flow of oxygenthrough the bypass 76 and 78 directly into the chamber 12. The attendantthen simply holds the face mask in position, but does not operate thebutton 28. Thus bypass flow of oxygen into the chamber 12 will besupplied within the face mask, and will be drawn into the casualty'slungs each time he breathes. Each time he exhales, the exhaled oxygenwill flow outwardly through the port 30. In order to economize inoxygen, the flow rate of oxygen can be carefully controlled bypositioning the knob 84, which may in fact carry a suitable marking (notshown) on its top surface indicating the approximate flow rate at anyposition. The casualty will then be able to breathe in, drawing in amixture of atmospheric air which can flow inwardly through the port 30,and additional oxygen flowing through the bypass. The precise balance orproportioning between air and oxygen will of course be up to theattendant. If he feels for example that the atmospheric air available isunsuitable or undesirable he can simply increase the oxygen flow ratethrough the bypass so that the casualty will be breathing 100% oxygen,and no air will flow in through the port 30 due to the excess of oxygensupplied to the chamber 12 through the bypass. On the other hand, if theatmospheric air is uncontaminated and suitable, then the oxygen flowrate could be reduced in order to conserve supplies.

In the event that the casualty has some obstruction in the windpipe,which has not become apparent to the attendant from his initialexamination, then when the attendant presses the button 28 to obtainpositive pressure resuscitation oxygen cannot flow from the face maskdirectly into the lungs. Thus the pressure within the chamber 12 willbuild up. It is of course essential to prevent any overpresure beyond acertain point since it might have the effect of either forcing theobstruction further down the windpipe for example. In order to preventsuch a build up of overpressure the pressure relief valve disc 38 andspring 48 are so set that the disc 38 will lift off the seat 40 if thepressure reaches 40mm. of mercury above atmospheric. Thus anyoverpressure in the chamber 12 will simply be released through thepressure relief valve mechanism, and will escape through the ports 58 or60 to atmosphere.

Similarly, if the equipment is being used by an inexperienced attendanthe may have a tendency to continue holding the button 28 shut long afterthe casualty's lungs have filled and the chest has risen. If there wereno provision for a pressure relief system such a method of operationcould be dangerous to the patient and result in over-dilation of thelungs. Again, this dangerous situation is avoided by presetting theblow-off pressure of the disc 38 by means of the adjustment screw 44 sothat the blow-off occurs precisely at 40 mm. of mercury.

Thus even with a completely inexperienced operator positive pressureresuscitation can be safely applied by means of the apparatus withoutdanger to the patient. In addition, the pressure relief valve beinglocated within the actual control device, will give an audible warningof the overpressure as soon as it develops. This is because theoperation of the valve is of course momentary that is to say it willlift off against its spring 48, release the overpressure and snap downagain and do so continuously fluttering up and downwardly, until theoperator releases the button 28, and removes the obstruction from thewindpipe. Similarly, this fluttering will occur if the button 28 is heldclosed after the lungs have been fully dilated. The fluttering of thevalve disc 38 provides an audible clicking sound which gives animmediate warning to the attendand that an overpressure exits so that hecan immediately act accordingly.

Preferably the flow rate of oxygen through the bypass B, when this is inuse, will be adjustable between about 0 - 15 liters per minute.

The flow rate available under positive pressure resuscitation, throughthe main body M will preferably be in the order of 70 liters per minute,although of course in this case, flow is intermittent, and oxygen willnot in practice be used at this rate.

The invention may therefore be summarised as providing chamber meansadapted to communicate with a face mask or like administration of saidgas; gas delivery means for delivering said gas from a suitable sourceof gas at an elevated pressure into said chamber; manually operable gasvalve means movable between a closed and open position and, whenreleased, remaining in its said closed position, for selective deliveryof gas thereto; normally open, free breathing air vent opening meanscommunicating with said chamber, permitting unrestricted free inhalationand exhalation through said chamber and said vent opening means;manually operable closure means for said vent opening means movablebetween a normally open, and a closed position for manually selectivelyclosing said vent opening means, said closure means being also connectedfor operation of said gas valve means whereby to cause delivery of gasto said chamber only when said closed position of said closure means hasbeen manually selected, said closure means remaining open, andpermitting inhalation and exhalation through said vent opening means,unless manually closed, and, pressure relief valve opening meanscommunicating with said chamber and a valve closure member normallyclosing the same and being responsive to the development of anoverpressure in said chamber for venting the same to atmosphere.

Reference has been made throughout to oxygen as the gas used. It willhowever be understood that gases other than oxygen could be administeredby use of the foregoing apparatus such as various types of anaestheticsor oxygen mixed with any other gas or gases, where the same provideadvantageous treatment.

The term oxygen used herein, is therefore to be taken as non-limiting,and it is intended that the term shall embrace any such gas or gases asmay be administered.

The foregoing is a description of a preferred embodiment of theinvention which is given here by way of example only. The invention isnot to be taken as limited to any of the specific features as describedbut comprehends all such variations as come within the scope of theappended claims.

What is claimed is:
 1. Apparatus for the administration of pressurizedgases, such as for resuscitation, inhalation or the like, said apparatuscomprising;a chamber having side walls, and an outlet adapted tocommunicate with patient administration means for administration of saidgas; a gas delivery conduit for delivering said gas from a suitablesource of gas at an elevated pressure into said chamber said conduithaving a free end terminating in said chamber and a gas flow orifice ina side wall thereof adjacent said free end for discharge of gas intosaid chamber; a manually operable gas flow control valve disposed insaid conduit and movable between a closed position and, when released,remaining in its said closed position, for selective delivery of gasfrom said gas flow orifice into said chamber; a normally open, freebreathing air vent opening in a side wall of said chamber inregistration with the free end of said conduit, permitting unrestrictedfree inhalation and exhalation through said chamber and said ventopening; a valve stem extending from said flow control valve, throughsaid vent opening for operation of said valve; a button on said valvestem, outside said chamber and having an outer and inner face, the innerface defining a vent closure for said vent opening said button beingmovable between a normally open, and a closed position therebyselectively opening and closing said vent opening movement of saidbutton also causing operation of said gas flow valve whereby to causedelivery of gas from said orifice to said chamber when the vent openingis closed by the inner face of the button, said vent opening remainingopen, and permitting inhalation and exhalation unless manually closed; apressure relief valve opening communicating with said chamber and avalve closure member normally closing the same and being responsive tothe development of an overpressure in said chamber for discharging thesame to atmosphere; a gas bypass connection connecting said gas deliveryconduit upstream of said flow contol valve with said chamber forreceiving gas independently of the control valve; a gas bypass flowvalve disposed in said by-pass connection and manually operable betweenopen and closed positions.
 2. Apparatus for the administration of gasesas claimed in claim 1, wherein said chamber is in the form of apassageway, formed in a main body portion, with said gas deliveryconduit communicating therewith through said main body portion, andwherein said passageway has two open ends, one said end adapted forcommunicating with patient administration means, and the other said endcommunicating with said pressure relief opening, and said vent openingbeing formed in said main body intermediate said ends.
 3. Apparatus forthe administration of gases as claimed in claim 2 wherein said pressurerelief valve member comprises a valve plate closure member for closingsaid other end of said passageway, spring means normally urging saidplate into said closed position, and being rsponsive to an overpressurein said chamber to lift off said end, and spring adjustment means foradjusting the setting of said spring.
 4. Apparatus for theadministration of gases as claimed in claim 1 wherein said pressurerelief opening communicates with said chamber, a pressure relief valvechamber located around said pressure relief opening, cover means for oneside of said pressure relief chamber, a movable valve plate within saidvalve chamber, normally closing said pressure relief opening and sealingthe same, spring means normally urging said valve plate into its closedposition, and, spring adjustment means incorporated in said covermember, and movably adjustable for adjusting the setting of said springmeans, and pressure relief vent openings communicating between saidpressure relief chamber and atmosphere.